Since its origins in the 1960s and commercialization in the 1990s, the Internet has expanded worldwide to become ubiquitous in social and business activities. When combined with wireless and high speed data links, many new applications have emerged. While the Internet was initially conceived as a communication medium for collaboration between users and applications, it relied on early web browsers that were limited to displaying static content to users. Web browsers now provide an increasingly rich execution platform that supports a variety of programming languages which allow web pages to respond to user input, dynamically update display screens, and issue asynchronous requests for new information. Web browsers can receive and transmit information between applications and the web browsers over the Internet in near real-time. Examples of these applications include handheld game controllers, meteorological data collection sites, webcam devices, and mobile phones and tablet computers that include cameras, Global Positioning System (GPS) receivers and removable data storage.
Despite increased sophistication and complexity of these applications, web browsers have been slow to allow low-level hardware devices to be accessed using JavaScript, the most popular client-side scripting language. This limitation has become particularly problematic as mobile processing units such as cellular phones and tablet computers include applications that leverage data from hardware devices including accelerometers, GPS receivers and removable storage. Concurrently, mobile processing units include increasingly powerful computational and storage capabilities. As the use of such mobile processing units increase, the requirement to access data from hardware devices will also increase.
In General, software programs must access hardware devices to interact with the outside world. Examples of hardware devices include hard disks, computer monitors, accelerometers, cameras, and microphones. Programs typically access hardware directly through the use of low-level assembly instructions, or indirectly through services provided by the underlying operating system. These traditional ways of device access arc problematic for three reasons. First, these low-level programming interfaces are often inconsistent and difficult to use, making it hard for developers to write programs that access hardware in sophisticated ways. Second, these programming interfaces often grant the software program wide-ranging capabilities to read and write to hardware devices. If the software program is buggy or malicious, it can wreak havoc with other programs and the user's data through the improper use of hardware devices. Third, low-level interfaces make it difficult for programs to interact with devices that are not directly co-located with the machine that is running a software program. For example, accessing a locally resident microphone is easily expressed, but accessing a microphone on a remote machine is difficult to express or impossible.
Ideally, applications could access hardware devices in a location-agnostic way using network protocols. These protocols would provide a narrow, simple interface, making them easy to secure and obviating the need for a large trusted computing base such as a browser.